Technical Field
The present disclosure provides compositions and methods for biologically producing fatty acid derivatives and, more specifically, using recombinant C1 metabolizing microorganisms to produce fatty alcohols, hydroxy fatty acids, or dicarboxylic acids from C1 substrates (such as methane or natural gas).
Background Description
Fatty alcohols are aliphatic alcohols that are predominantly linear and monohydric. They are composed of a nonpolar lipophilic, saturated or unsaturated hydrocarbon chain, usually from C6 to C24, and a polar, hydrophilic hydroxyl group attached to the terminal carbon. Fatty alcohols are high value chemicals with a multitude of applications, such as surfactants, detergents, lubricant additives, defoamers, solubility retarders, and consistency giving factors. Fatty alcohol production capacity was approximately 2 million metric tons per year in 2009. Included in the capacity are C12/C14 alcohols, C16/C18 alcohols, and C15/C18 alcohols. The global surfactant market is expected to reach $16.65 billion by 2012. Nonionic surfactants constitute the second largest group of products in the surfactant market. Fatty acid based surfactants represent some 20% of the nonionic type of surfactants.
Currently the fatty alcohol market is dominated by natural alcohol and synthetic alcohol products. Natural alcohols are prepared from natural oils, fats, and waxes of plants or animals, such as coconut or palm oil, using transesterification and hydrogenation processes. Synthetic alcohols are produced from petrochemical feedstocks such as ethene, olefins and paraffins, mainly from the Ziegler alcohol process, SHOP process, and Oxo process. However, these processes either require harsh production environments, questionable land use practices, or environmentally detrimental byproducts.
Increasing efforts have been made to enable microbial production of fatty alcohols from abundant and cost-effective renewable resources. In particular, recombinant microorganisms, such as E. coli and various yeasts, have been used to convert biomass-derived feedstocks to fatty alcohols, such as lauryl alcohol. However, even with the use of relatively inexpensive cellulosic biomass as a feedstock, more than half the mass of carbohydrate feedstocks is comprised of oxygen, which represents a significant limitation in conversion efficiency. Long chain fatty acids and their derivatives (such as fatty alcohols, hydroxy-fatty acids, fatty aldehydes,) have significantly lower oxygen content than the feedstocks, which limits the theoretical yield as the oxygen must be eliminated as waste. Thus, the economics of production of fatty acids and their derivatives from carbohydrate feedstocks is prohibitively expensive.
In view of the limitations associated with carbohydrate-based fermentation methods for production of fatty alcohol and related compounds, there is a need in the art for alternative, cost-effective, and environmentally friendly methods for producing fatty alcohols. The present disclosure meets such needs, and further provides other related advantages.